Speed of light

see aether wasn't quackery like astrology or alchemy

nope

Why? That's the question, and it was never answered.

it's inconsistent with the theory and the theory works in so many other cases, and so much of other verifiable science won't work if the theory is broken, that we infer it's impossible

If something went FTL, what would break?

I knew the theory works sometimes, it's inconsistent with the theory, and people think it's impossible before I started the thread.

the theory would break. that's a possibility of all theories.

but before we observe such an event, our confidence that such an event could happen would be so low it's not reasonable to consider it possible

Don't think of the speed of light as something fundamental to only light, it is a limit on any type of information traveling, light, matter, even things like gravity, you will not be affected by gravitational fluctuations from an event 5 light-years away until 5 years after it happens.

Using Newtonian mechanics, one would expect to be able to continue to add energy to an object and have it travel faster and faster in an additive sort of way, this is they way, this is the way we intuitively understand velocity because it is a good approximation at low energies, however it is technically incorrect even then, its just that the difference too small to be detectable. In reality as you add more and more energy, a massive body's velocity asymptotically approaches c, getting closer and closer but never able to reach it. You ask what would break, I don't know how to give any answer other than that it would take an infinite amount of energy to reach c in the first place (or zero mass such as a photon).

Right. But who's to say there isn't a particle with less mass than a photon that travels faster?

Is it just that we've never seen such a thing, so we don't look for at and assume it can't happen?

Is it possible that it happens, but our brains are limited by the speed of light (or, realistically, even slower), so we have no hope of observing it if it does?

Right. It was a legitimate idea, which just happened to be wrong.
I suppose I could argue that alchemy was legit too. Newton believed in it. They didn't know enough then to realize that no amount of mixing and heating would turn lead into gold. Many alchemists were quacks and con-men. Some were undoubtedly sincere in their beliefs. They just happened to be wrong.

>every single observation and experiment agrees on the finite speed of light
>"extraordinary claim"

In the standard model photons have 0 mass. If this were not the case it would definitely be revolutionary, a lot of fundamentals would have to change, however this is very unlikely, we observe c not just from light but from plenty of other sources as well. For example neutrinos which are not mass-less but extremely light we measure to be almost exactly the same, in addition we can observe that things do asymptotically approach the same speed when we add more and more energy, in particle accelerators we continuously add energy and observe massive particles going from 99% c to 99.999% to 99.9999999% etc. Even gravitational waves have recently been detected explicitly from what is thought to have been a black hole merger, and the data aligns.

>Right. It was a legitimate idea, which just happened to be wrong.

Unless cold fusion is real, in which case you discouraged an idea that would allow us all to be living in gold houses right now just to conform to other people's expectations.

Maybe some did figugre it out and just didn't share?

That's a logical fallacy called "appeal to authority".

>cold fusion
>not just cold fusion but cold fusion on a scale that would be economically justifiable to produce gold
what are you on mate

>Is it just that we've never seen such a thing, so we don't look for at and assume it can't happen?
We've looked for it every single time we've got an inkling that it might be true. Scientists love that shit. If it turns out to be a real phenomenon they could base their whole career chasing it down.

The FTL neutrino thing was discounted not because everyone threw their hands up and said it couldn't be real, but because they wanted to see if it was real and rigorously tested it to rule out experimental error.

appeals to authority aren't necessarily logical fallacies

it is a logical fallacy, however logical fallacies don't necessarily lead to incorrect results (such as this case)

okay go do the experiments yourself. or actually learn something and go look up maxwell's equations

no, it's sometimes categorically not a fallacy. an appeal to authority that cites a recognized expert in the field making a statement generally accepted by the field as true, is not a fallacious argument.

What if there was an invisible demon suppressing the results?

We'd never know, because it's invisible.

There is no particle with less rest-mass than a photon because a photon has zero rest-mass.
Particles with imaginary mass, called tachyons,
have been postulated. They could ONLY travel faster than light. But any theory which includes them turns out to have contradictions in the mathematics -- things like the probability of an event occurring working out to be greater than one. That can't be.

There are several reasons why information cannot be sent faster than light. The mass-increase is just one of them. SF writers might accept that you can't go past lightspeed by simply accelerating, but they try to get around that by postulating shortcuts though hyperspace or some-such technobabble.

It doesn't work. FTL travel is equivalent to being able to go backwards in time. This violates causality; i.e. effects precede causes, rather than the usual cause-and-then-effect. The universe would be a mad place! Since this doesn't seem to happen (and because of a century of experiments which have ALL confirmed Relativity) we have great confidence FTL is impossible. What said.
It is possible that Einstein may prove, someday, to be only an approximation of a better theory (one which meshes with quantum mechanics) but that better theory will still have to explain the vast body of evidence we've gathered.

Tesla's were better

You can use their argument without it being a logical fallacy, but saying "everyone thinks it must be true, so it is" is always a logical fallacy, and science gets repressed all the time based on it.

it is reasonable to say you believe in something because the authorities agree on it, but that isn't strictly logical argument for it's truth, the OP is asking why something is that way it is, I would say it is fallacious to answer that question with "the experts all think it is"

Isn't zero anything an imaginary construct, anyway?

And what if some idea behind statistics is logically flawed or doesn't mesh well with parts of reality we haven't observed, and our understand of reality as humans is warped as fuck?

>I would say it is fallacious to answer that question with "the experts all think it is"
i don't. the experts know the theories and they know the available evidence. they know the evidence that supports the theory and they know the evidence which might be contrary to the theory.

if they know all that and they still think it's unlikely for the hypothesis to be true, i trust them.

None of the alchemists ever got rich (except by bilking their patrons) and none lived forever (their other great goal). I take that (plus modern atomic theory -- which works!) as proof none succeeded.

When you show me cold fusion, I'll give your argument some credence. But not until.
Anyone can hypothesize. "What ifs" are cheap.

Anyone is free to carry out an experiment overthrowing energy conservation, Relativity, anything you like. As a practical matter, re-doing ALL past experiments to check that the results in books really happened is impractical. Science is self-correcting. Lies, errors, mistakes, self-deception all come out eventually. Look up "N-rays", for example.
Your logical fallacy is assuming generation after generation of scientists are all participants in a vast conspiracy to Hide the Truth.

Zero is as real as any other point on the number-line. If your bank tells you there's zero dollars in your account, do you protest that can't possibly be?

Again, "If... If... If...".
"If the Sun doesn't rise tomorrow..." Possible. But all the evidence (so far) says it will.

>Everyone thinks it must be true, so it is

This is an appeal to popularity, not to authority

Oh my god, no. No to this whole set of comments, and not to you in particular.

The only reason to have a theory of anything is for predictive power - otherwise, I can make up any ridiculous theory and you have no ground to tell me not to use it. So to say that using a theory because it agrees with an overwhelming body of evidence is somehow fallacy is utter garbage.

>This is an appeal to popularity, not to authority
Correct but science hits this roadblock all the time. Academia is very cliquish, and history is littered with examples of people who were correct but got squashed because they were challenging accepted scientific orthodoxy. The conceit that we're any better nowdays is just flat out wrong, academics are more insular and unwilling to consider outside viewpoints than ever and the trend of relying on scientific consensus as evidence in and of itself is still prominent. Just look at climate change. The argument that "95% of all climate scientists agree!" is used over and over? So what? 95% of all scientists have always been wrong about something or other and appealing to the favorite theory of the time just because it's well supported it MUST be true is just retarded

I'm not disagreeing with you on that, I just pointed out that the description you gave of an appeal to authority wasn't an appeal to authority.

The speed of light has been slowing down over the duration of the universe. It's on a logarithmic curve and the only reason we don't notice it continuing to slow is because we started using clocks based on the speed of light, so our reference point that measures time is changing at the same rate as the speed of light changes.

Have you ever heard of peer review?

You know there are plenty of examples of scientists whose peer review work was ignored because it contradicted the scientific consensus at the time only to be later proven right? Pretending that the peer review process actually ensures that research is judged on it's merits is a little bit naive to say the least when many scientists have had to die before their work would be taken seriously.

>is there some non-theoretical, consistently observed evidence for why people think light has a speed limit?

>sometimes it's a logical fallacy, sometimes it isn't
People like you is why others shoud be aware of logical fallacies.

>If your bank tells you there's zero dollars in your account, do you protest that can't possibly be?

Yes. Because money is also an imaginary construct backed by nothing. Like zero, it exists nowhere but the human imagination. So you can use zero to desribe things in the human imagination, but there's no zero or infinity in the real world.

There were mathematics before there was zero, and too many people probably get stuck treating zero and infinity as if they are things the universe conforms to.

In this case, it's both.

> to say that using a theory because it agrees with an overwhelming body of evidence is somehow fallacy is utter garbage.

But to say "everyone else believes it" or "respected people believe it" IS a logical fallacy.

>The speed of light has been slowing down over the duration of the universe

How the hell do you know that?

Please tell me you're trolling.

Trolling is against the rules of boards other than /b/.

What did I say that was wrong?

It's the theory that best fits the data

>Why does light have to have a speed limit?
It doesn't

>is there some non-theoretical, consistently observed evidence for why people think light has a speed limit?
no

Theories aren't facts, and you shouldn't present them as such or people could get confused.

Why not?

Sorry, it's the hypothesis that best fits the data.

How else woukd you expect to justify things that only a reduced group of the population understands? Appeal to authority would be that you outright deny or take as fact something because someone said so without making a case for it. Saying that someone who has studied most of his life and is an expert on a subject has more qualifications to talk about that subject is you not appealing to authority but building up a case by showing his/her credentials. Also, infomal logic is trash and only useful for people who out right conclude something ONLY using those arguments. If you say "no scientists worth it's salt would back up climate change as a hoax", and just keeping it like that would be a no true Scotsman fallacy. Saying "No true scientist would believe that because..." and then arguing why it goes against the defining aspects of science by doing so would not be a fallacy, but a construction of an arquetype that you argue is needed for science to work. Also, yea, scientific exploration is not deductive reasoning it's a mixture of both, but the underlying truth is alway taken wrt to the empirical aspect of it, that is, if the experiment contradicts the theory, we kill the theory. So you cannot make deductive arguments without basing yourself on the data itself which is something few people have acces too. If you want to challenge Newton's results you are free to corroborate his astronomical comparisons by you measuring them again and see if it fits his predictions, or you could take that considering the succes and impact his discoveries have had on our society, it's enough to give a justification of the science as discovered by experts.

...

Wow, nice pents. Checked.

Also, tl;dr. You're wrong, it's a fallacy, I'm not reading that.

No-one said you couldn't personally take scientific consensus as proof of something. Just that you can't use it to support an argument. "This group of experts all agree on x" is a fallacy and you can't use an argument like that to support any point.

If 4/5 dentists agree that Colgate is the best toothpaste is good enough for you to decide to always use Colgate toothpaste you go right ahead and do that. No-one said you couldn't. If you're going to go up to other people and assert that you believe colgate is the best toothpaste you're going to need something more convincing than "most dentists agree it's the best!"

>it had to be incredibly rigid to account to the high speed of light, but it also had to let the planets pass through it without drag.
This is not necessary. New theories are build around idea of ether as gas.

>They all failed.
Wrong

I'm not reading that wall-o-text.

I'm assuming you're telling me about trusting the experts. I agree, most of the time we should rely on them... still a logical fallacy though.

here are many articles about ether if anybody interested orgonelab.org/energyinspace.htm

So if I have string longer than two light years, and I pull it, what happens?

It moves?

Yes, If I'm personally not convinced, maybe I'm going to do research and what dp you know, I may even find that there was a scandal where Colgate donated to some scetchy fund that has ties with a lot of mainstream scientists and there's claims that the study asked only a select group of dentists whatever. The problem here is understanding the fundamental differences between formal and informal fallacies. Formal fallacies are true were you to accept laws of logic wich in most casea are classical. After that any argument made in this language can be rigorously constructed and maybe proven. Informal logic is more of a set of thumb rules that has no real backbone, but are really useful when trying to make an argument valid, but they wil always be context sensitive. In this case, if 2 people who have almost no knowledge about a topic, but one says this community of experts on the topic say that this statement is true it's not blalant appeal to authority as it's really all the information it has. Now the problem with science is that at the end you rely on the data and the best way to show the evidence is to show the articles that have been accepted by the community and we reach a problem because few people will get past the abstract. The arguments made itt were that that's just what the experiment tells us because that's what the scientists doing the experiments report to us, there's no way you can prove something like "the speed of light is independent of frame of references" by pure deduction, or well you would need to rely on other framework of truth such as the Maxwell equations which inevitably will lead to tell them well we get those equations based on scientific discovery. Ideally, people who cite scientific papers should also understand them, but it's a completely ridiculous statement, but if you expect to gain full understanding of theae topics through some unorganized chitchat you are delusional, but yoare always welcomed to tryand study for yourself.

But why should we rely on? That's you elevating the statement from fallacy to some aort of argument. There's a reason we trust scientists for many things, but why? I would love to explain my reasoning behind it, from philosophical stances, historical event and data to simple experiments you can do in your house, just not in this format, but there's reasoning behind why scientific citations constitute a reasonable defense. But also bare with me, would you actually expect people to enter an hour long rant about why trusting scientists its a good idea? If you have a particual case were you can show that trusting blind scientific data isn't necessarily a good idea, but again like I posted here
Informak fallacies are rules of thumb, so I could pompously name a fallacy of "equationf science with authority fallacy, fallacy" or some shit like thay, because as a rule of thumb, using the arguments brought by the scientific community generally constitutes a good case. In law, no one really asks the full methodology of foresincs, but they trust it will give information that may be relevant and revealing to some case.

> no slack

The pull travels through it at the speed of sound (in the string).

Lol

What would it mean for light to be instantaneous?

Well, if E=MC^2 and C goes to infinity, then so does E for any finite M.
So the first atom bomb would have blown up the entire universe.
As would the first star which started fusing.
And the first subatomic reaction after the Big Bang.

But why can't photons go lower than the speed of light?

Three explanations.
1. Maxwell's equation yield a particular speed and no other
2. Lightspeed is a fundamental constant of our universe; the conversion factor between lengths and times. Do you ever ask why electrons couldn't have some different charge or the gravitational constant could vary?
3. Photons have no rest-mass. All of their energy is wrapped up in their "energy of motion". If a photon slowed, it would have less energy. Where would the lost energy have gone?

It's commonly said that photons travel slower through solids like glass. That's an illusion. The photon is interacting with the electric fields of the atoms it passes near, constantly being absorbed and re-emitted. Whether the photon which emerges on the far side of a window is "the same" photon which entered is a matter of semantics.

If you need further convincing, I'm afraid you'll have to crack a physics text.

Sauce, please.
Something peer-reviewed preferably.
And don't give me the old "evidence has been suppressed by the Scientific Orthodoxy!" crap.
A single experiment (or astronomical observation) which showed faster light in some previous era would win a Physics Nobel hands-down.
"Extraordinary claims (and this would be one of the MOST extraordinary) demand extraordinary proof."

>Minkowski recognized (as Einstein had not) that the speed of light is simply a conversion factor between units of distance and units of time. 1 second = 300,000 km. It's no more esoteric than converting feet to meters.
>Nothing with rest-mass can attain the speed of light (or exceed it). Nothing without rest-mass (mainly photons) can travel at any speed EXCEPT that of light. The recently-detected gravity waves travel at lightspeed.
With the exception of this, I can attest everything is correct.

What's your beef? Minkowski? Einstein initially thought Minkowski's "geometrical" interpretation was an unnecessary complication, but came to appreciate its utility. He probably couldn't have created General Relativity later on without that insight.

Or is it something in the second line?

Okay
Try to tell your landlord that next time you see him, Karl

>Just that you can't use it in a rigorous logical proof
fixed

you can use scientific consensus in an argument all you want

>the speed of light is simply a conversion factor between units of distance and units of time
Either this makes no sense or this means everything moves at the speed of light which is wrong.

>But why can't a photon go faster than the speed of light?
Light is photons. They travel at the speed of light by definition.

Everything DOES move at the speed of light.
Wait. Don't start an angry rebuttal just yet.

Look up Minkowski diagram. Space-axis (X) runs horizontally, time-axis runs vertically. Usually scaled so an arbitrary unit (like an inch) equals 300,000 km or 1 second. Therefore, light always travels along 45 degree lines.
Something (call it A) which isn't moving (with respect to you) runs straight up the T-axis at 1 (scaled) inch per second. If A IS moving, its vector is the same length, but tilted somewhat. Motion in space comes at the expense of motion in time.
A, of course, always considers himself stationary. His (tilted by your reckoning) path defines HIS T-axis. Call that T-prime since I can't write superscripts here. His X axis also deviates from yours. If you drew his T-prime to point clockwise of your T, then his X-prime is rotated counter-clockwise of your X. Only thus can the velocity of light remain invariant. It always bisects the angle between the X and T axes. Anybody's X and T axis.
That rotation in the "opposite" direction is why the geometry of Relativity is hyperbolic instead of a euclidean rotation. Time is subtracted, rather than added, in computing the Interval between events so all observers measure the same Interval even though they may differ in their separation into space and time.

If my word-picture is unclear, see en.wikipedia.org/wiki/Minkowski_diagram

Photons cannot travel faster than light. If you impart more energy to them, you just increase their frequency.

Don't Maxwell's equations directly lead to light moving slower in glass because of the change in epsilon?

Gravitational waves are different from gravity itself.

Gravity acts instantaneously. A ripple in space time caused by a gravitational fluctuation is a gravitational wave. Those travel at approximately the speed of light.

Gravity in it of itself tho is instantaneous action at a distance.

The speed of light is actually the speed of causality, this means that there is actually a limit on how fast things can happen in this universe.

I believe that's a macroscopic viewpoint. I'm looking at Volume 1 of the Feynman Lectures, paragraph 31-1. "The Origin of the Refractive Index". Too long to quote in full here, but...

"It is approximately true that light or any electrical wave DOES APPEAR to travel at the speed c/n through a material whose index of refraction is n, but the fields are still produced by the motion of ALL the charges -- including the charges moving in the material -- and with the basic contributions of the field traveling with the ultimate velocity c. Our problem is to understand how the APPARENTLY slower velocity comes about." (I've capitalized where Feynman's transcriber used italics.)

In volume 2 he more fully discusses Maxwell's equations and explains why Maxwell got the right answers (which is what counts!!) even though his "mental model" was incorrect.

I hope this at least shows you were to look for a better explanation than I can offer here.

Also, at the point which the speed of causality will be breached, things start getting heavier, which slows things down. The more things try to be faster than causality, the heavier they get, and the slower they become -- something like that.

Stop responding to this stuttering pothead

>Gravitational waves are different from gravity itself.
TRUE!
>A ripple in space time caused by a gravitational fluctuation is a gravitational wave.
TRUE!
>Those travel at approximately the speed of light.
FALSE! The waves travel EXACTLY at the speed of light.
>Gravity in it of itself tho is instantaneous action at a distance.
FALSE Gravity does not act instantaneously.
This is a myth promulgated by people like Van Flandern who thought that a much higher velocity than cee was necessary for energy and angular momentum conservation.
en.wikipedia.org/wiki/Tom_Van_Flandern
Putting it briefly, we see the Sun where it was 8 minutes ago. If gravity pointed towards where it was 8 minutes ago, there would be a retarding force on the Earth's motion.
Actually, this "lag" is precisely cancelled by the gravitational analog of optical aberration. See references 38 and 39 at the bottom of the Wikipedia article.

>All of their energy is wrapped up in their "energy of motion". If a photon slowed, it would have less energy. Where would the lost energy have gone?

I thought x-rays and gamme rays are faster than UV and microwaves and visible light.

wat

Why? He thinks that zero is real and tangible.

It's exactly the same as our economy, which runs on the Tinkerbell Theory.

Just like in Peter Pan, where a fairy dies every time we say won't believe in fairies, and comes back to life when we change our minds, that's the world economy.

Your money is backed by nothing. It's an intangible concept, like zero, which also has no existence in the real physical world.

A badly-written summary of Minkowski diagrams won't convince me. And nowhere do I read that everything moves at the speed of light. The time axis of the Minkowski diagram doesn't count.

Nice. That doesn't answer the question at all, you dumb retarded fuck.

The speed of light is a rate of induction and nothing else. All it is is a perturbation of the bloch wall using electricity and magnetism.

Do you all actually believe that "light" is being emmited from something? Do you think light moves?

>It's commonly said that photons travel slower through solids like glass.
Because it does, the "speed" of "light" is not constant see:
>That's an illusion. The photon is interacting with the electric fields of the atoms it passes near, constantly being absorbed and re-emitted. Whether the photon which emerges on the far side of a window is "the same" photon which entered is a matter of semantics.

It slows down and speeds back up out of glass because glass is also capacitor (dielectric capacitor). That's why the wavelengths of light come out at different angles in a prism, smaller the space (of a wave) the higher the capacitance. Red light has a larger spacial footprint than blue end light which is why it "diffracts" less when it goes through glass.

Don't waste your time with people who have no concept that "0" does not exist. The mathematicians like their special little placeholder and big bang theory relies on something coming from nothing. They always fail to find a "0" in nature though and usually when I ask them to find one they bring up yet another human contrivance of bean counting.

They actually believe that the universe understand math and has a calculator that positions particles around at specific points in "space".

spoken ad ignorantiam

>Why does light have to have a speed limit?
Einstein postulated that
/thread

>Nothing without rest-mass (mainly photons) can travel at any speed EXCEPT that of light. The recently-detected gravity waves travel at lightspeed.
So what about quantum entanglement?

>Why does light have to have a speed limit?
It doesn't

en.wikipedia.org/wiki/Fizeau_experiment
>According to the theories prevailing at the time, light traveling through a moving medium would be dragged along by the medium, so that the measured speed of the light would be a simple sum of its speed through the medium plus the speed of the medium.
>Fizeau indeed detected a dragging effect